BOSTON - The state Senate passed legislation Thursday that would require a better organized and quicker repair of the estimated 20,000 leaks in the state's natural gas pipeline system.

"We have gas utilities companies that are not properly repairing gas leaks, so we actually have to pass regulations to address when those should be repaired. Itís a disturbing commentary on private companies with millions of customers," said Sen. James Eldridge, D-Acton.

Between 2002 and 2012, there were 23 significant incidents on gas pipelines statewide that caused deaths, dozens of injuries and millions of dollars in damage. In Hopkinton in July 2002†an early-morning natural gas explosion at 65 Main St. ripped apart the four-unit apartment building where the Carey†family lived, killing†4-year-old Iris and 5-year-old Violet.†In 2006, NStar paid $17 million to†the girls' parents just†days before the civil lawsuit was to go to trial.

The Senate's legislation would create a new classification system for the repair of natural gas leaks.

Grade One leaks, the most hazardous, would require immediate repairs. Grade Two leaks would have to be fixed within 12 months and reevaluated every six months, while Grade Three leaks would be reassessed every 12 months.

While an amendment that would have required new gas pipelines be consistent with the 2008 Global Warming Solutions Act did not pass, Clean Water Action, an environmental group, said that the specific repair timeline is progress.

"It really is a day to celebrate. This is a much stronger bill than the version passed in the House in February, and that's because of progressive Senate members," said Clean Water spokesman Joel Wool.

Amendments filed by Eldridge, in particular, would increase public safety by prioritizing leaks near heavily populated†areas such as places of worship and municipal buildings, said Wool.

Sen. Karen Spilka, D-Ashland also voted for the bill, calling the leaks a threat to public safety.

"I am proud to support this legislation, which takes important steps to repair our aging infrastructure and reduce the costs and dangers of gas leaks in our communities," she said in a statement.

The House bill's original author, Rep. Lori Erhlich, D- Marblehead, says the state's natural gas pipeline system - the oldest in the country - is riddled with some 21,000 leaks.

An August 2013 study commissioned by Sen. Edward Markey found that Massachusetts gas companies replaced less than 4 percent of their leak-prone pipes per year compared to the national average of less than 5 percent.

In the last three years, Boston Gas has replaced an average of 150 miles of pipes per year, according to spokesman David Graves. NStar did not provide similar information.

Representatives from both companies said they support the bill.

"This is an important piece of legislation that will accomplish a number of objectives: It will increase public safety by accelerating the replacement of older leak prone pipe, reduce the level of natural gas that is lost due to gas leaks, and standardize the identification and repair of gas leaks," said National Grid spokesman Jake Navarro.

Page 2 of 2 - Both versions of the gas leaks legislation now head to a conference committee to hammer out any differences.